Valves for regulating flow of liquids and gases in relatively large diameter pipes are typically gate valves and butterfly valves.
Stem valves, which may include butterfly valves and gate valves having rising and non-rising stems, are widely used as oil field valves for production of oil and gas. Such valves are typically situated outdoors and are thus exposed to elements such as rain and snow, and further often regulate flow of oil and gas which may contain fluids [which in an unrefined state contain impurities such as sour gas (hydrogen sulfide)] which may cause corrosion and thus seizure of internal moveable valve components. A further exacerbating factor and serious problem in and of itself is that valves of this type are frequently located in remote oilfield locations, and are thus not able to be lubricated regularly and maintained.
Accordingly, even though such valves have a greasing zerk to allow lubrication, frequently due to lack of regular lubrication seizure of such valves and resulting inability to open or close such valves is a serious problem.
Once seized, such valves must often be disconnected from the wellhead equipment and replaced. Replacing such valves is not an easy task, requiring service professionals, and moreover transporting such service professionals and equipment to remote locations to carry out such task. Accordingly, replacement of seized valves by removal requires a substantial cost.
Even though some valves, depending on their condition, once removed can be disassembled and reconditioned at a service facility, the servicing cost is likewise high, to say nothing of the cost of removing the valve and replacing with a re-conditioned valve, and thereafter transporting the seized valves to a service facility for reconditioning,
Accordingly, a real need exists, particularly in the oilpatch, for a tool and method that allows unseizing of seized valves of this type in-situ, without having to remove such valves and re-install a reconditioned unit and transport the seized valve to a reconditioning facility.
US Publication 2014/0124298, having a common inventor with the invention herein, teaches a tool and method for unseizing seized valves, in situ, to thereby avoid having to remove such seized valves from piping on which they are installed, for servicing.
Specifically, as may be seen from FIGS. 3 & 4 of US Pub. 2014/0124298, the tool 63 taught therein comprises a housing 65 having a moveable piston 85 within a bore 71 of tool 63. Tool 63 may be pinned to the rotating member of the valve 11 to which the valve handle 59 was formerly affixed. Piston 85, when the tool 63 is pinned to the rotating member (ie actuator 45) of valve stem 33, may be used to first inject a solvent into the body of the valve 11 to unseize threaded components (such as the actuator 45 of the valve 11), and thereafter upon the valve thereby becoming unseized, the tool may further be the used to inject grease into the valve 11 via a greasing zert. Thereafter, tool 63 may be unpinned from the rotating member (actuator 45) of the valve 11, and the handle 59 re-attached to valve 11 to thereafter allow normal opening and closing of unseized valve 11.
Disadvantageously, however, the tool and method disclosed in US Publ. 2014/0124298 only indirectly, through flow of solvent through a circuitous route, provides solvent or grease to actuator member 45 on valve stem 33, particularly if threads on actuator are significantly corroded and does not force such fluid/grease directly onto threads on valve actuator member via injection across a valve seal 53 within valve stem 33 of valve 11 to thereby unseize such threads and actuator. Alternatively, de-rusting fluid, penetrating solvent and/or grease, when injected by piston 85 into greasing zert (injection passage 49) flows out over valve seal 53 if worn following the path of least resistance, particularly if other areas of the valve are more corroded, and fails to penetrate regions of the valve which may be heavily corroded, such as the slidable gate member 25 of valve 11, thus failing to allow the de-rusting fluid and/or penetrating solvent to unseize the seized areas of the valve.
Further disadvantageously, the tool 63 disclosed in US Publ. 2014/0124298, at least in the form as commercialized, is inoperable should the valve be seized in the fully closed position. Specifically, while tool 63 may be pinned to the rotating member of the valve 11 forming part of the rising stem of valve 11 is in the slightly open to fully open position, when such rotating member (and thus the valve 11) are in the fully closed position, due to the depth of the tool 63 and the foreshortened distance of exposed rotating member, in its commercialized format the tool 63 is then unable to be pinned to valve 11, and is thus inoperable and ineffective in rendering operable and lubricating valves in such condition.
Accordingly, a real need exists in the oil patch for a tool and method which is able to better force penetration of de-rusting fluid or penetrating oil to render movable seized valve components in seized valves, and thereafter be able to likewise supply grease to such areas.